Hi marcoss46210423,
we recently had some users in the forum that couldn't rename objects in the Layers panel and one who couldn't rename states of an MSO. The reason is a bit unclear, could be a bug with your version of InDesign and the version of the operating system. For the renaming issue in the Layers panel Rob Day wrote an ExtendScript (JavaScript) that is working on a selected object. For example your MSO that refuses to be renamed using the MSO panel.
One solution was:
"Undock the Layers Panel and let it float. Clicking on the name should now allow the name to be edited. It appears that this feature doesn't work for renaming Page Items that are under the layers if the Layers Panel is docked."
https://community.adobe.com/t5/indesign/how-do-you-rename-a-sublayer-object-in-the-layer-s-panel-of-indesign-2021/m-p/11671904#M407509
The other solution was Rob's script when the object, in your case your MSO, was selected.
The code for this ExtendScript (JavaScript) is posted in this thread:
https://community.adobe.com/t5/indesign/can-t-rename-layers-indesign-2021-16-0-also-happened-in-2020/m-p/11613408#M404598
Regards,
Uwe Laubender
( ACP )